Escherichia coli (hereinafter also referred to as E. coli) is a Gram-negative, short rod bacterium of genus Escherichia, family Enterobacteriaceae, and one of normal flora found in intestines of various animals including mammals. Most strains of E. coli are non-pathogenic and can cause opportunistic infection, but some highly pathogenic strains cause various intestinal diseases and sepsis in animals including humans.
Escherichia coli can be classified into enterotoxigenic Escherichia coli (ETEC), enteropathogenic Escherichia coli (EPEC), enterohemorrhagic Escherichia coli (EHEC), enteroaggregative Escherichia coli (EAEC), enteroinvasive Escherichia coli (EIEC), necrotoxigenic Escherichia coli (NTEC), and the like, and particularly, enterotoxigenic Escherichia coli is known to cause infectious diseases in pigs.
Currently, with the trend toward large-scale group housing in pig farming, porcine colibacillosis has emerged as the most frequent and bothering disease in pig farms. Recently, outbreaks of porcine colibacillosis, which stunts piglet growth due to diarrhea and mortality, have been increasing in Korea, causing enormous economic loss to pig farmers.
For prevention and treatment of porcine colibacillosis, although various antibiotics have been applied to pigs in the related art, abuse or misuse of antibiotics can induce antibiotic resistance in pigs or can cause the antibiotics to remain in the pigs' body, leading to global restrictions on administration of antibiotics.
Meanwhile, a bacteriophage refers to a bacteria-specific virus capable of infecting a specific bacterium and preventing and inhibiting growth of the bacterium. As bacteriophages have stronger host specificity than antibiotics, and recent emergence of bacteria resistant to antibiotics and residual antibiotics in animals are growing problems, application of bacteriophages has drawn great interest.
Studies on bacteriophages have been actively performed in many countries, and there has been an increasing tendency to obtain approval from the Food and Drug Administration (FDA) for compositions using bacteriophages in addition to patent applications for bacteriophages.
However, bacteriophage related technologies for prevention and/or treatment of infectious diseases, which are important issues in the livestock industry including pig farming, due to enterotoxigenic Escherichia coli are still insufficient and therefore, there is a need for such bacteriophages and development of relevant technologies.